Sealing constructions



2 Sheets-Sheet 1 Filed NOV. 27, 1959 Dec. 4, 1962 B. P. BAKER SEALINGCONSTRUCTIONS 2 Sheets-Sheet 2 Filed NOV. 27, 1959 \iW/ 36 mm E & a

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United States Patent Ofice Patented Dec. 4, 1962 3,066,823 SEALINGCONSTRUCTIGNS Benjamin P. Baker, deceased, late of Monroeville, Pa.,

by Mellon National Bank and Trust Co., executor,

assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., acorporation of Pennsylvania Filed Nov. 27, 1955 Ser. No. 855,760 2Claims. (Cl. 220-46) This invention relates to sealing constructions ingeneral, and, more particularly, to scaling constructions for insuringthe containment of a fluid within an enclosing vessel.

A general object of the present invention is to provide an improvedsealing construction for containers containing 21 fluid. The term fluidas employed herein includes gases, liquids, vapors and sprays.

The present invention has particular applicability in the case of largedevices, such as sulfur-hexafluoride sealed power circuit breakers ofthe type set forth and claimed in United States patent application,filed January 23, 1959, Serial No. 788,668, by Russel N. Yeckley, JosephSucha and Benjamin P. Baker, and assigned to the assignee of the instantapplication. In the aforesaid patent application there is illustratedand described a power circuit interrupter of considerable rating,namely, 15,000 mva., and employing pressure vessels containingsulfur-hexafluoride gas under pressure, say 60 p.s.i.

It is an object of the present invention to provide an improved sealingarrangement for pressure vessels of the type described in the aforesaidapplication.

Another object of the present invention is to provide improved means fordetecting leaks at the gaskets employed in sealing constructions forcontainers containing a fluid.

Another object of the present invention is to provide an improvedsealing construction involving a pair of spaced concentric annulargaskets, the space between which may communicate with a detecting bore,which is adaptable for receiving the detecting end of a leak detector.

Still a further object of the present invention is to provide animproved sealing construction involving a pair of concentric gaskets,the space between which communicates with a detecting bore, in whichprovision is made for injecting, under pressure, a semi-plastic caulkingcompound into the annular space between said annular gaskets forassisting in preventing leaks at the seal.

Further objects and advantages will readily become apparent upon readingthe following specification taken in conjunction with the drawings, inwhich:

FIG. 1 is a perspective view of a three-pole power circuit interrupterof the type employing pressure vessels, which contain a sealed gas underpressure; FIG. 2 is a considerably enlarged, vertical sectional viewtaken through the upwardly extending terminal-bushing supportof FIG. 1,illustrating the improved sealing construction of the present invention;and,

FIG. 3 is an enlarged sectional view taken through the rotatableoperating shaft-seal for the circuit interrupter of FIG. 1, showing anapplication of the present invention to the shaft-seal.

Referring to the drawings, and more particularly to FIG. 1 thereof, thereference numeral 1 generally designates a high-voltage, high-power,fluid-blast circuit interrupter, adaptable for the control of athree-phase transmission circuit, whose lines are indicated by thereference numerals L L L L L L As noted in FIG. 1, there is provided anelongated tank structure 2 for each poleunit of the circuitinterrupter 1. The pole-units may generally be designated by the lettersA, B and C. The poleunits are identical in construction; consequently, adescription of the operation of one pole-unit, for instance, pole unitA, will suflice for an understanding of the operation of pole-units Band C, which are identical. As illustrated in FIG. 1, a weatherproofenclosing tube 3 encloses an axially movable operating rod, whichmechanically interconnects the three pole-units A, B and C forsimultaneous operation, so that there is no relaying difficulty. Anaccelerating spring housing 3a is disposed at the end of the stationaryweatherproof tube 3, within which is disposed an opening acceleratingspring, not shown, which biases the enclosed operating rod axially tothe right, as viewed in FIG. 1.

A mechanism and gas-control housing 4 is disposed adjacent to the tankstructure 2 of front pole-unit A, and not only houses a ratherconventional pneumatic mechanism for effecting the axial motion of theenclosed operating shaft within tube 3, but also the housing 4 enclosesthe equipment for maintaining the dual-pressure, gas-supply system atthe desired pressures.

Each of the tank structures 2 includes a generally horizontallyextending cylindrical tank portion 5, which has a pair of hinged closurecaps 6 at its opposite ends. The hinged closure caps, or heads 6, may beswung to an open position about their hinges, to permit the lateralWithdrawal of an arc-extinguishing assemblage, not shown, from the tankstructure 2 during maintenance operations.

Reference may be had to the aforesaid patent application for a detaileddescription of the manner of operation of the arc-extinguishingassemblage, which is positioned within each of the three tank structures2, and is supported at the lower ends of the terminal bushings 12, 13,which extend downwardly through cylindrical bushing supports 11, thelatter being welded to the upper sides of the tank structures 2.

The present invention is, in part, particularly concerned with sealingconstructions for providing a sealed mounting connection between each ofthe terminal bushings 12, 13 and the upper end of the cylindricalterminalbushing support 11. In addition, the present invention isparticularly concerned with a sealing construction for each of the endclosure caps 6, which must be opened during service operations performedupon the interrupters.

The present invention is also concerned with a shaftsealing constructionfor transmitting power externally of the tank structure 2 interiorlythereinto.

-In the manufacture of sulfur-hexafluoride (SP circuit breakers, wherethe gas must be contained at pressures varying from 30 p.s.i.g. to 1,000p.s.i.g., it is necessary to be able to detect very small leaks. Thiscan be done by adding a very small trace of CCl, or Freon to the SP andthen snifling with the halogen leak detector, or some other suitablemeans.

This is a rather slow operation and difficult to perform when notshielded from wind and weather. Some of these seals involve doors, suchas the end caps 6, for the interrupter 1 of FIG. 1, 36 inches or more indiameter, which must be removed in the field for inspection andmaintenance.

To overcome these difficulties, it is proposed to use two gaskets, orO-rings placed in separate grooves with the space between themcommunicating with the outside, such as shown in FIGS. 2 and 3 of thedrawings. With such constructions, three very desirable eifects havebeen obt-ained.

First, the sniffing element of the leak detector, not shown, can beinserted into the opening 7 and any leaks past the inner ring, or gasket9, regardless of its size, can be immediately detected. Such anoperation is not affected by wind, weather or contaminating atmosphere.

If the inner gasket 9 shows a small leak, and it is not convenient tomake repairs, detecting bore 17 can be sealed, employing a sealed plug18, and the outer, second gasket 19 used as a back-stop.

A third advantage is that if both gaskets '9, 19 leak, and it isimpractical to take the circuit interrupter 1 out of serviceimmediately, some semi-plastic caulking compound, such as an elastomericsilicone compound, can be pumped into the space 20 between the inner andouter gaskets 9, 19, respectively.

Elastomeric polyester may also be used. Polyurethane foam, which has thecharacteristics of expanding after it is pumped into position, could beused to seal small cracks between the inner and outer gaskets 9, 19, andlikewise pumped under pressure into the detecting bore 17 and into thespace 20.

It will be noted that the sealing construction employed in the presentinvention is very simple in application. It is only necessary to providea pair of sealing grooves 21 in a sealing member 22. This sealing member22, as shown in FIG. 2, may constitute the upper flanged extremity ofthe terminal-bushing cylindrical support 11. Or, as shown in FIG. 3, thesealing member 22 may constitute a flanged mounting support 23,constituting a part of a shaft-mounting assembly 24, which is employedto provide a shaft-seal in transmitting power through the wall of asealed tank 2.

The rotatable shaft 25 may have an internal lever 26 fixedly secured tothe inner end of the shaft 25. Secured to the outer end of the rotatableshaft 25 is an external lever 27, which is employed to effect rotationof the shaft 25. One end of the shaft 25 may be rotatably guided byroller bearings 28, 29, as shown in FIG. 3.

The inner end of the rotatable shaft 25 may have associated therewith aplurality of abutting polytetrafluoroethylene V-rings 30, which may bemaintained under pressure by a washer 31 and a compression spring 32.One end of the compression spring 32 is advantageously maintained intoposition by an annular support cap 33, secured by bolts 34 to theflanged mounting support 23 of the shaft mounting assembly 24.

Fixe-dly securing the shaft-mounting assembly 24 into position throughthe wall 5 of the power circuit-interrupter tank 2 are bolts 36. Withreference to FIG. 1, the longitudinally movable operating rod, disposedwithin the surrounding weatherproof tube 3, is employed to effectrotation of the external operating lever 27, and hence effectcorresponding rotation of the internal operating lever 26. The rotationof the internal operating lever 26 is effective to open the contactstructure and the blast valve associated with each of thearc-extinguishing assemblages, not shown, disposed longitudinallyinteriorly within each of the tank structures 2, and supported thereinby the lower interior ends of the terminal bushings 12, 13, in a mannerset forth in detail in the aforesaid patent applica tion.

With reference to FIG. 2, it will be noted that the groundedflangedsupport plate 37 of the terminal bushing 12 is suitably secured,as by a plurality of bolts 38 to the flange member, or sealing member22, which is welded, as at 39, to the upper extremity of the cylindricalbushing support'll. Thus, the lower surface 40 of the flange plate 37makes abutting engagement with the O-rings 9, 19 for a fluid-tightengagement. Similarly, the mounting support 41 (FIG. 3), which iswelded, as at 42, to the cylindrical wall 5 of the tank structure 2,makes abutting contact with the first and second gasket means, 9-, 19,respectively, associated with the shaft-mounting assembly 24; As before,the resilient first and second gasket means 9, 19 are mountedinconcentric grooves-21 provided in the flanged mounting support 23.

It will be obvious, from the foregoing description of the invention,that either the end flange 43 (FIG. 1) welded to the end of thecylindrical section 5, or the flange portion 44 of the end closure cap 6may be provided with spaced concentric sealing grooves 21, as in FIGS.2. and 3,

l and may have associated therewith similar ring-shaped annular gaskets9, 19.

'From the foregoing description, it will be apparent that there isillustrated and described an improved sealing construction, which may beeither asociated with a shaftseal or with static closure membersassociated with a fluid-tight container containing any suitable fluid,which it is desired to retain in a sealed manner. Such a sealingconstruction may be employed in connection with each of the pole-unitsA, B, C illustrated in FIG. 1, it being noted that in the case of eachpole-unit there are employed five sealing locations. This is apparentwhen it is realized that there are two end caps 6, each of which has asealing construction of the type set forth in FIGS. 2 and 3 associatedtherewith. In addition, each pole-unit has two upwardly extendingcylindrical bushing supports 11, each of which has a sealingconstruction, such as illustrated in FIG. 2 of the drawings. Moreover,the longitudinally movable shaft, disposed within enclosing tube 3, hasto be connected to the external lever 27 and have power therefromtransmitted through the wall 5 of the tank structure 2. This shaft-sealis of the type set forth in FIG. 3 of the drawings. As a result, thereare fifteen sealing locations associated with the entire threepole powercircuit interrupter illustrated in FIG. 1. Since the gas, such assulfur-hexafiuoride gas, is retained under pressure within each of thesealed tank structures 2, it is readily apparent that a highly effectiveseal is desirable, which, in addition, it is desired to associate withthe possible use of a leak-detector device.

By removing the pipe plug 18, associated with the detecting passage 17,and inserting the detecting end of a leak detector into the opening 7,as mentioned, the accumulation of gas within the detecting passage 17may readily be detected without hindrance from the atmospheric elements.

There are many choices of sealing caulking compounds available for usein injecting them under pressure within the detecting passage 17, andinto the space 20 between the first and second gasket means, 9, 19,respectively. The above examples were given only by way of illustration.Others will be readily apparent to those skilled in the art.

Although there have been illustrated and described various types ofsealing constructions, it is to be clearly understood that the same weremerely for the purpose of illustration, and that changes andmodifications may readily be made therein by those skilled in the artwithout departing from the spirit and scope of the invention.

Accordingly, what is claimed as new is:

1. In a sealing construction between two sealing members havingsubstantially fiat abutting surfaces, one of said members beinggenerally annular and having passage means therethrough containing fluidwhich it is desired to seal, a pair of spaced annular concentric gasketgrooves in the contacting surface of one of said sealing members, theother sealing member being flat at the point of contact, an annularresilient gasket disposed in each of said gasket grooves, the depth ofthe two gasket grooves being less than the uncompressed thickness of thegaskets, the outer of the two gasket grooves having a width which isgreater than the width of the resilient gasket disposed therein whencompressed to define an annular sealing passage whereby the annularsealing passage may serve as a reception space for a sealing fluid,means defining a detecting passage communicating at one end with saidannular sealing passage and at the other end with a point external tosaid one sealing member, and a single removable closure means forclosing the external end of said detecting passage.

2. In a sealing construction between two sealing members havingsubstantially flat abutting surfaces, one of said members beinggenerally annular and having passage means therethrough containing fluidwhich it is desired to seal, a pair of spaced annular concentric gasketgrooves in the contacting surface of one of said sealing members, theother sealing member being flat at the point of contact, an annularresilient gasket disposed in each of said gasket grooves, the depth ofthe two gasket grooves being less than the uncompressed thickness of thegaskets, the outer of the two gasket grooves having a width which isgreater than the width of the resilient gasket disposed therein whencompressed to define an annular sealing passage whereby the annularsealing passage may serve as a reception space for a sealing fluid,means defining a detecting passage communicating at one end with saidannular sealing passage and at the other end with a point external tosaid one sealing member, a semi-plastic sealing compound forced throughsaid detecting passage and into said annular sealing passage, and asingle removable closure means for closing the external end of saiddetecting passage.

References Cited in the file of this patent UNITED STATES PATENTS2,208,778 Stuart July 23, 1940 2,460,054 Wiggins Jan. 25, 1949 2,492,409Worn et a1. Dec. 27, 1949 2,510,417 Rehklau June 6, 1950 2,590,803 Ungeret al Mar, 25, 1952 2,727,286 Moore Dec. 20, 1955 2,750,069 Gross June12, 1956 2,760,673 Laurent Aug. 28, 1956 2,840,262 Learmonth et al June24, 1958 2,921,608 Crawford et a1 Ian. 19, 1960

